The invention relates to an inductive miniature component for SMD-mounting with a coil support formed of synthetic or ferrite material, in or on which coil support is arranged at least one coil winding, whereby outwardly projecting connection pegs are arranged on an outer side of the coil support and formed therewith as a single piece with each connection peg having several turns of an end of a respective winding wire of a coil wire wound therearound, as well as a method for producing a component of this type.
An inductive miniature component of this type having a coil support comprised of a ferrite is described, for example, in German Utility Model Number 298 24 118.8.
In components of this type, the problem occurs with winding wires having very small diameters such as, for example, a diameter less than 0.08 mm, that the connection technology by which the end of the winding wire is secured by several turns around the connection peg becomes critical in view of the strength of the connection when subjected to a drop test and a vibration test. The danger exists that the ends of the thin winding wire are torn off in response to the loading thereof.
The invention provides a solution to the challenge of configuring an inductive miniature component for SMD-mounting with the features as set forth in the introductory portion and the principal concept of the patent claim 1 in such a manner that even with the deployment of winding wires having very thin diameters, the danger of a tearing off of the end of the winding wire is, even during shock vibration loading, considerably reduced.
The solution to this challenge succeeds, with reference to the component configured in accordance with the features set forth in the characterizing portion of the patent claim 1, in that a respective metallized wire winding comprised of an electrically conducting wire is disposed between each connection peg and the end of the winding wire wound therearound with the diameter of the electrically conducting wire being greater than the diameter of the winding wire and several turns thereof are wound directly on the connection peg. Advantageous modifications of the invention are described in the dependent claims as well as further described hereinafter in connection with the embodiment examples. A method for producing the inventive component is characterized by the following method steps:
a) positioning in readiness a coil support with outwardly projecting connection pegs;
b) winding of the connection pegs with several turns of a metallic wire winding, whereby the diameter of the wire is greater than the diameter of the winding wire;
c) disposition of a coil winding in the coil support;
d) removal of the lacquer insulation on the ends of the winding wire and, as the occasion arises, preliminarily applying tin to the ends;
e) winding of the connection pegs having the metallic wire winding wound therearound with several turns of the ends of the winding wire of the coil winding;
f) placing the coil support ends in contact with the connection pegs via dip brazing.
A further method for producing the inventive component is characterized by the following method steps:
a) positioning in readiness a coil support with outwardly projecting connection pegs;
b) winding of the connection pegs with several turns of a metallic wire winding, whereby the diameter of the wire is greater than the diameter of the winding wire;
c) disposition of at least one coil winding on the coil support;
d) removal of the lacquer insulation on the end of the winding wire and, as the occasion arises, preliminarily applying tin to the ends;
e) winding of the connection pegs having the metallic wire winding wound therearound with several turns of the ends of the winding wire of the coil winding;
f) placing the coil support ends in contact with the connection pegs via dip brazing.
The core concept of the invention lies in the fact that the respective ends of the winding wires are not directly wound on the connection pegs but, instead, the connection pegs are initially wound with several turns of a wire. Several turns of the ends of the winding wires are then wound around the metallic wire windings which have previously been wound on the connection pegs. Via the pre-applied winding onto each of the connection pegs of an electrically conducting wire of greater diameter, there are produced wide metallic surfaces which are similar to metallic connections. It has been shown that, in this manner, connections can be achieved which are mechanically substantially more stable than connections having the ends of the winding wires directly wound onto the connection pegs.
The diameter of the wire of the metallic wire winding should be sufficiently large that the wire""s resistance to breakage under tension or tensile strength is sufficient to handle the impact loading and shake loading of the component. It has been shown that it is advantageous if the wire of the metallic wire winding has a diameter which is at least twice as great as the diameter of the winding wire.
The wire of the metallic wire winding can be a copper silver (CuAg) wire but can be, as well, a copper silver (CuAg) wire having a pre-applied tin application or a wire having an alloy formed of a high tensile strength such as, for example, bronze.
The inventive connection technology is deployable with both coil supports formed of plastic or synthetic material as well as with coil supports formed of ferrite and ceramic plates. The arrangement of the connection pegs can be as desired and can be accommodated to the respective usage purposes.
In the following description, an embodiment of the inductive miniature component of the invention is described in more detail with reference to the attached drawings.